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Author Topic: Panasonic servo drive help  (Read 62401 times)

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Offline Hood

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Re: Panasonic servo drive help
« Reply #150 on: April 14, 2013, 05:37:27 PM »
Looked at the manual and although I didnt read from end to end I dont see any mention of a parameter for setting the alarm output. It would be unusual for that to be the case as mentioned its a dedicated output and not configurable so no need to have parameters.
Maybe it is blown :(
Hood

Offline rwf71

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Re: Panasonic servo drive help
« Reply #151 on: April 14, 2013, 06:20:14 PM »
Thanks Hood,
    I haven't had a chance to look myself yet but I'm betting your right about no parameter, Probably right about blown as well. Do you reckon I blew it by checking/hooking relay between 26 and ground? Seems like we agree that 26 should be the alarm out I wanted to use so I'll get another axis done and hook 26 to 24v first next time and see what it does. If I'm understanding you correctly now, 26 is just a ground anyway so hooking ground to ground should not have caused any harm, if it is blown hopefully I didn't do it. ::)

    AS ALWAYS, THANK YOU for your time & patience,    Rick

Offline Hood

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Re: Panasonic servo drive help
« Reply #152 on: April 14, 2013, 06:26:51 PM »
According to the manual you put 24v in to the output and the output completes the circuit to ground when active.
Dont know enough about electronics to say whether you could damage by connecting to ground :(
Hood
Re: Panasonic servo drive help
« Reply #153 on: April 14, 2013, 07:34:48 PM »
Hi Guys,
  Rick, you might try your relay on the Servo Ready output on pin 27 as a test. :)
It will operate opposite of the Alarm, ie: ON when ready and OFF when not but it might verify that you are wired correctly and that the Alarm output opto has in fact popped.
  The notes on page 22 are key also ....  the load limit, snubber (which I see you have) and damage from reversed polarity.
Russ
  :)

Offline rwf71

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Re: Panasonic servo drive help
« Reply #154 on: April 16, 2013, 12:19:36 AM »
Thanks for the reply Russ,
    Still getting my head around this, I may have even had the snubber diode the wrong way round as well. I think I'm getting it but just seems wrong to put power into a pin labeled as an output. :-\ I,m not saying you guys are wrong, no way!, I'm saying it's wrong/misleading that Panasonic calls pin 26 "servo alarm output" but what it really does is provide a ground for completing the circuit. In this hillbillies mind you don't put power into an output, ::), I guess it's because I didn't know about or understand this "sinking" & "sourcing" stuff.
    When I put the diode across the relay I had it reversed biased for power to come out of the output, apparently power flows the other way so diode was forward biased. I know it's wrong now, but still seems right to me that power should come OUT of a pin labeled output, not go IN. >:(

     Rick

Offline Hood

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Re: Panasonic servo drive help
« Reply #155 on: April 16, 2013, 03:14:26 AM »
Yes it does sound strange but that is the way it can be. The Allen Bradley drives I use have sinking Ins and Sourcing outs, the Samsungs have Sourcing Ins and sourcing outs, however the outs have both positive and negative  sides to the connections coming out the drive so you can supply 24v to the positive terminal and connect to the negative terminal and thus basically you are getting a 24v out. The Telemcanique you can choose with a jumper whether you want sinking Ins/Sourcing outs or the other way round.
Confusing stuff indeed, electronics is a strange world ;D


Hood

Offline rwf71

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Re: Panasonic servo drive help
« Reply #156 on: April 16, 2013, 05:51:49 AM »
My Grandpa used to say, "you learn something new everyday". I like learning new stuff and consider it a good day when I do,but I just hate learning from a mistake though :-[. I guess it's OK as long as you LEARN and not repeat them! After Russ used the term "optocoupler" I read a little about them, seems a lot of them are built in a dual inline package (dip), I would like to replace the optocoupler because I really want this alarm monitoring capability in my system but considering what a servo drive and electronics expert I am I'm not sure if I should try it or not, chances and pretty good I could make things worse instead of better :o.

                        Rick  

Offline Hood

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Re: Panasonic servo drive help
« Reply #157 on: April 16, 2013, 06:57:39 AM »
Quite possible to do and I suppose also quite possible to make it worse, risk you take  ;D
You will need to look inside and get the part number off the opto and get one the same, you will likely find its a surface mount device and it will likely be small so you need to have decent soldering skills. I have replaced line drivers and such on some drives and it was fairly straight forward but plenty of flux and also solder wick make things easier. After you have it done look very closely to make sure you have no solder bridges before you put power to it or you may release the magic smoke.
Hood
Re: Panasonic servo drive help
« Reply #158 on: April 16, 2013, 07:09:03 AM »
I've got a Hillbilly view of this here stuff myself ... try to look at it this way.
You have to supply 24V I/O power for this unit to its + and - terminals.
The output opto's in the drive simply open or close the circuit from the output terminal to dc+.(-50ma load)
The drive is in essence just a relay to toggle the output pin ON and OFF.
Look at your external relay as a LED or light bulb instead, (drawing - 50 ma). The drive would just turn it on and off.
So, you are not really applying power IN to an OUTPUT, you are applying a LOAD to the output and the drive is completing the path to ground for you ... with it's opto (acting as a relay coil internally)
The fact that you are operating a relay coil instead doesn't really matter (as long as the load is low and the diode stops the surge.
The illustration on page 22 looks a bit deceiving at a glance as it shows what looks to represent SPST switches .... where in actuality, I think it is just illustrating that the outputs are normally ON or OFF as depicted.

That's my unofficial Northern Appalachian view,
Russ  ;D
 
« Last Edit: April 16, 2013, 09:23:39 AM by Overloaded »
Re: Panasonic servo drive help
« Reply #159 on: April 16, 2013, 07:37:38 AM »
was looking at the manual on a small laptop and the illustration shifted.  >:(
Ignore the "illustration" statement above. ::)
sorry,
Russ ;D